As an exact like-for-like replacement for the original equipment Omron unit, complete with wiring and power transistor, this unit fits straight into the relevant Makita battery drills quickly and easily. The connectors to the battery shoe can be sticky but look for a small catch in each terminal which will release it. It's ideal if your speed control has failed. It's worth noting that this item contains all the electronics and wiring in the drill, so fitting it is very straightforward. No soldering is required, just a small Philips screwdriver. Allow about 15 minutes.